Marshall: Hey, babe, did you know that Robin was going through a mourning period? I mean, she seemed fine after the breakup.
Lily: Oh, you know how she is. She tries to keep her emotions to herself. But, yeah, I caught her crying a couple times. She cried? Like real tears? But that means... Oh, no.
Future Ted: [v.o.] And then Marshall realized what a jackass he'd been to Robin.
[flashback to the gang at MacLaren's:]
Marshall: Exactly. Barney's dating again and he couldn't be happier. I mean, that guy has been active. Sexually. All right, he's just been like, bang, bang, bang! You know? It's like, bang, bang, bang, bang. [singing] Bang, bang, bang, bang, bang, bangity bang I said a bang, bang, bang, bangity bang bang, bang, bang Bang, bang, bangity bang I said a bang, bang, bangity bang.
[present:]
Marshall: How could you let me do that? You're my wife. You're supposed to stop me from embarrassing myself in public.
Lily: I know. But that song's kind of catchy. [singing] Bang, bang, bangity bang
Both: [singing] Bang, bang, bangity bang I said, bang, bang, bangity bang Bang, bang, bangity bang